Why are ketones/aldehydes more oxidized than alcohols?

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In summary, we discussed the reasons for ketones/aldehydes being more oxidized compared to alcohols. This is due to the presence of more oxygen bonds in ketones/aldehydes, which results in a higher oxidation state for the carbon atom. We also learned that the oxidation state of an atom can be determined by following certain rules, including the number of oxygen and hydrogen bonds and the overall charge of the molecule. These concepts can be further explored on a website created by Borek, which focuses on redox reactions and balancing with oxidation numbers.
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hivesaeed4
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I thought that the reason was the presence of a double bond would allow oxygen to exert a stronger pull on the electrons making the co bond as compared to when their was only a double bind between the two but then I remembered that inductance happens only through sigma bonds So why are ketones/aldehydes more oxidized as compared to alcohols?
 
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  • #2
Many ways of skinning that cat.

First, and the simplest one - try to assign oxidation numbers to the carbon in methanol and methanal.

Can you write reaction equation of the R-CH2OH (a general primary alcohol) being converted to R-CHO (a general primary aldehyde)? What is removed from the alcohol molecule? How is the removed substance related to oxidation/reduction processes?
 
  • #3
Yep. Think in terms of oxidation state of the carbon atom.
 
  • #4
Well you remove hydrogen and so that in itself is oxidation.

But I don't remember the oxidation states/numbers. I learned them in high school and don't exactly remember them. Why don't you tell me how to evaluate the oxidation state of the carbon atom. I tried understanding it from other online sources yet I didn't really understand it and am pretty sure that you guys would do a better job at it than websites do.
 
  • #5
The more oxygen bonds a carbon has the more oxidized it is. An alcohol has one and ketones or aldehydes have two. Carbon dioxide has four and represents the most oxidized form of carbon in this series. A little different than memorizing the oxidation numbers of atoms you saw back in HS.
 
  • #6
hivesaeed4 said:
But I don't remember the oxidation states/numbers.

I tried understanding it from other online sources yet I didn't really understand it and am pretty sure that you guys would do a better job at it than websites do.

Really? I already prepared a website that explains these things, why do you think I will be better here than there:

(...)
Oxygen in almost all compounds has oxidation number -2.
Hydrogen in almost all compounds has oxidation number +1.
(...)
Last rule says that the charge of the ion or molecule equals sum of oxidation numbers of all atoms.
 
  • #7
Thanks. By the way what was the name of the website your talking about Borek? I'd like to visit it. (I really didn't know you created one).
 
  • #9
Thanks. Nice website.
 

1. Why are ketones/aldehydes more oxidized than alcohols?

Ketones and aldehydes are more oxidized than alcohols because they contain a carbonyl group, which is a highly reactive functional group. The presence of this group makes them more susceptible to oxidation reactions.

2. What is the difference between the oxidation levels of ketones/aldehydes and alcohols?

Ketones and aldehydes have a higher oxidation level compared to alcohols. This is because they have a double bond between the carbon and oxygen atoms, which increases the number of bonds between the carbon and oxygen atoms. This higher bond order leads to a higher oxidation state.

3. How does the structure of ketones/aldehydes contribute to their higher oxidization level?

The structure of ketones and aldehydes plays a crucial role in their higher oxidization level. The carbonyl group, consisting of a carbon atom double-bonded to an oxygen atom, is highly reactive and easily oxidized. This reactivity is further enhanced by the presence of other functional groups attached to the carbonyl carbon, such as alkyl or aryl groups.

4. Can alcohols be oxidized to form ketones/aldehydes?

Yes, alcohols can be oxidized to form ketones or aldehydes. This process is known as the oxidation of alcohols and requires the use of a strong oxidizing agent, such as potassium permanganate or chromic acid. The oxidation of alcohols to form ketones or aldehydes is an important reaction in organic chemistry and is widely used in the synthesis of various compounds.

5. Are there any exceptions to the general rule of ketones/aldehydes being more oxidized than alcohols?

Yes, there are some exceptions to this rule. For example, when comparing primary alcohols to ketones or aldehydes, primary alcohols can be more easily oxidized due to the presence of a hydrogen atom attached to the carbon atom next to the hydroxyl group. This hydrogen atom can be easily removed, resulting in the formation of a carbonyl group. Additionally, the presence of certain functional groups, such as electron-withdrawing groups, can also affect the oxidization levels of alcohols and ketones/aldehydes.

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